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Subject[PATCH 5.3 301/344] i40e: check __I40E_VF_DISABLE bit in i40e_sync_filters_subtask
Date
From: Stefan Assmann <sassmann@kpanic.de>

commit a7542b87607560d0b89e7ff81d870bd6ff8835cb upstream.

While testing VF spawn/destroy the following panic occurred.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000029
[...]
Workqueue: i40e i40e_service_task [i40e]
RIP: 0010:i40e_sync_vsi_filters+0x6fd/0xc60 [i40e]
[...]
Call Trace:
? __switch_to_asm+0x35/0x70
? __switch_to_asm+0x41/0x70
? __switch_to_asm+0x35/0x70
? _cond_resched+0x15/0x30
i40e_sync_filters_subtask+0x56/0x70 [i40e]
i40e_service_task+0x382/0x11b0 [i40e]
? __switch_to_asm+0x41/0x70
? __switch_to_asm+0x41/0x70
process_one_work+0x1a7/0x3b0
worker_thread+0x30/0x390
? create_worker+0x1a0/0x1a0
kthread+0x112/0x130
? kthread_bind+0x30/0x30
ret_from_fork+0x35/0x40

Investigation revealed a race where pf->vf[vsi->vf_id].trusted may get
accessed by the watchdog via i40e_sync_filters_subtask() although
i40e_free_vfs() already free'd pf->vf.
To avoid this the call to i40e_sync_vsi_filters() in
i40e_sync_filters_subtask() needs to be guarded by __I40E_VF_DISABLE,
which is also used by i40e_free_vfs().

Note: put the __I40E_VF_DISABLE check after the
__I40E_MACVLAN_SYNC_PENDING check as the latter is more likely to
trigger.

CC: stable@vger.kernel.org
Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/intel/i40e/i40e_main.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -2583,6 +2583,10 @@ static void i40e_sync_filters_subtask(st
return;
if (!test_and_clear_bit(__I40E_MACVLAN_SYNC_PENDING, pf->state))
return;
+ if (test_and_set_bit(__I40E_VF_DISABLE, pf->state)) {
+ set_bit(__I40E_MACVLAN_SYNC_PENDING, pf->state);
+ return;
+ }

for (v = 0; v < pf->num_alloc_vsi; v++) {
if (pf->vsi[v] &&
@@ -2597,6 +2601,7 @@ static void i40e_sync_filters_subtask(st
}
}
}
+ clear_bit(__I40E_VF_DISABLE, pf->state);
}

/**

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